Pumping container



Nov. 18, 1969 M, AUD TE ET AL 3,478,696

PUMPING CONTAINER Filed April 12, 1968 5 Sheets-Sheet 1 COLD INVENTOR.

M/C'HAEL 4. 40057716; ANN-,4 4. 40057 2,

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NOV. 18, 1969 L, AUDETTE, ET AL 3,478,696

PUMPING CONTAINER 3 Shets-Sheet Filed April 12, 1968 z4A/l754 A.40057-75,

BY v

' I wma/x/ 47441? United States Patent U.S. Cl. 103236 12 ClaimsABSTRACT OF THE DISCLOSURE A fluid pump assembly of the steam injectiontype consisting of a tank having a top chamber and a bottom chamber. Thebottom chamber contains a boiler portion with an electric heater. Afloat valve mounted in the bottom chamber controls admission of steaminto the bottom chamber from the boiler portion. Tandem-operating valvesare provided in the top walls of the top and bottom chambers. The topvalve is normally open and elevated and contains a capsule containingmercury which expands responsive to heat, moving the valve from open toclosed position. This also closes the bottom valve. Steam from thebottom chamber can enter the top chamber and acts on the mercury capsuleto cause the two valves to close. Trapped steam in the top chambercondenses, creating a vacuum. The top chamber is connected to a liquidsource. The vacuum draws the liquid into the top chamber, causing themercury capsule to cool and causing fluid pressure to be developed inthe top chamber, whereby to re-open the tandem valves. The liquid flowsinto the bottom chamber, acting on the float valve to cut ofl the flowof steam when the level in the bottom chamber reaches a desired height.The assembly is provided with a hot-and-cold fluid-mixing outlet conduitsystem connected to the bottom chamber.

This invention relates to fluid distribution systems, and moreparticularly to a fluid pump assembly of the steam injection type whichmay be employed for the purpose of pumping fluids of various types, suchas water, gas, oil, or the like, from a source to a distribution conduitsystem or other distination.

A main object of the invention is to provide a novel and improved fluidpump of the steam injection type, the pump being relatively simple inconstruction, being relia ble in operation, and being adaptable for usewith a wide range of fluids. Thus, the pump assembly may be used toconvey liquid, such as a refined sea water for long distances, or may beused as a pumping part of a pipeline system.

A further object of the invention is to provide an improved pumpingsystem for delivering fluids, such as water, gas, oil, or the like, froma supply source to a distributing conduit system, the pump involvingrelatively few moving parts, being relatively compact in size, beingeconomical to operate, and requiring a minimum amount of maintenanceattention to keep it in operating condition. A still further objectof'the invention is to provide an improved fluid pump of the steaminjection type for pumping liquids, such as water, gas, oil, or thelike, the pump being inexpensive to fabricate, being inexpensive toopcrate, being provided with emergency operating means which may be usedin the event that the main source of power for the pump breaks down,andbeing provided with a mixing system for regulating the temperature ofliquid withdrawn therefrom.

A still further object of the invention is to provide an improved fluidpump of the steam injection type which employs a control valve systemwhichvis thermally-operated in a novel and highly eflicient manner, thepump 3,478,696 Patented Nov. 18, 1969 valve system thereby being reducedto a relatively small number of parts and being adapted for long periodsof operation without the need for frequent inspection or repair.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

FIGURE 1 is a vertical cross-sectional view taken through an improvedfluid pump assembly constructed in accordance with the presentinvention.

FIGURE 2 is an enlarged vertical cross-sectional view taken through anupper corner portion of the assembly of FIGURE 1, and particularlyshowing the construction of the actuating mechanism for the tandemvalves of the ump.

FIGURE 3 is a horizontal cross-sectional view taken substantially on theline 33 of FIGURE 2.

FIGURE 4 is a horizontal cross-sectional view taken substantially on theline 4-4 of FIGURE 2.

FIGURE 5 is an enlarged fragmentary vertical crosssectional view takensubstantially on the line 5--5 of FIGURE 4.

I FIGURE 6 is an enlarged horizontal cross-sectional view takensubstantially on the line 66 of FIGURE 1.

FIGURE 7 is a vertical cross-sectional view taken substantially on theline 7-7 of FIGURE 6.

FIGURE 8 is an enlarged fragmentary vertical crosssectionl view takensubstantially on the line 8-8 of FIGURE 1.

FIGURE 9 is a fragmentary horizontal plan view taken substantially onthe line 99 of FIGURE 8.

FIGURE 10 is a vertical cross-sectional view taken substantially on theline 10-10 of FIGURE 8.

Referring to the drawings, 11 generally designates. an improved pumpassembly, constructed in accordance with the present invention, employedfor the purpose of pumping water from a supply source 12 to adistribution system, for example, to the water distribution system of adwelling. Thus, the pump assembly may be located in any convenientportion of the dwelling, for example, in the basement, and the pumpassembly is connected to the water supply source 12 by any suitable typeof conduit, such as the conduit 13 shown in FIGURE 1. The pump assemblyhas an outlet conduit 14 for general distribution, and is furtherprovided with a hot-and-cold water-mixing system, designated generallyat 15, presently to be describedin detail.

The fluid pump assembly 11 comprises a tank 16 which is provided with anintermediate horizontal partition wall 17 which divides the tank into atop chamber 18 and a bottom chamber 19. The water inlet conduit 13 isconnected to top chamber 18 at the top wall 20 of said top chamber, asis clearly shown in FIGURE 1. The conduit 13 extends to the supplyreservoir 12, whose top surface may be on a level substantially lowerthan that of top wall 20, as shown.

The lower portion of tank 16 includes a boiler chamber 21 whichcommunicates with the lower; chamber 19 through a horizontal conduit 22mounted on the bottom wall 23 of the tank and extending through thelower marginal portion of the main wall of the tank. Thus, the boilerchamber 21 comprises a lateral extension of the, lower portion of thetank. However, it communicates with the lower chamber 19 of the tank.

A conventional electric heating unit 24 is provided at the bottom ofboiler chamber 21 immediately beneath conduit 22, as shown in FIGURES l,8 and 10. The heating unit 24 includes the generally semicylindricalopposing inner segments 25, 25 which are mounted in the conduit 22 andwhich are separated by a mass of refractory material 26 through whichextends suitable heater windings (not shown), forming part of the heaterassembly. Thus, the inner sections 25, define a pair of water-flowchannels leading from chamber 19 to the interior of boiler chamber 21.

Conduit 22 has an end wall 27 located in chamber 19, but is providedwith an aperture 28 in its top Wall opening into chamber 19 and allowingthe water in chamber 19 to enter conduit 22 and flow therethrough in thegenerally, semicylindrical opposing Sections 25, 25 to the interior ofboiler chamber 21. The heater Windings extend around the conduitsections 25, 25 and also between their adjacent inside walls 29, 29.Thus, the heat-conducting conduit sections 25, 25 provide suflicientconduction of heat from the heater windings to the water flowing throughthe conduit sections to keep the water boiling.

Boiler chamber 21 is provided with a hot water outlet conduit 30 leadingto the mixing valve system 15. Another conduit 32 leads from the lowerportion of the chamber 19 to divert cold water into the mixing valvesystem 15, as is clearly shown in FIGURE 1. The mixing valve assembly 15is provided with an outlet conduit 33 and with an adjustableproportioning valve assembly 34 of generally conventional constructionfor adjusting the proportions of the hot and cold water admitted throughconduits 30 and 32 allowed to pass to the outlet conduit 33. The mixingvalve system 15 may be provided with a manually-operatedmixture-adjustment knob 35, or alternatively, may be provided with aconventional thermostatically-controlled, manually-settable mixing valvemechanism, if so desired.

Boiler chamber 21 has a top wall 36, and rising from said top walladjacent the vertical wall of tank 16 is a generally cylindricalvertical chamber 37 having a top wall 38 provided with a conventionalsafety valve 39. concentrically-secured inside the chamber 37 is anothercylindrical shell element 40 (FIGURE 7), and slidably androtatably-disposed between shell 40 and main cylindrical chamber 37 is asleeve 41. Sleeve 41 is provided at its upper portion with an aperture42 which is registrable with an aperture 43 provided in shell 40 whenthe sleeve 41 is in a relatively elevated position. Aperture 43registers with an aperture 44 provided in the upper portion of the wallof chamber 19. Thus, when aperture 42 is in registry with the apertures43 and 44, communication is established between the interior of shell 40and the upper portion of chamber 19.

Sleeve 41 is provided with an aperture 45 in its lower portion which isregistrable with a pair of registering apertures 46 and 47 provided,respectively, in shell 40 and the cylindrical outer wall 37, as shown inFIGURE 7, when the sleeve 41 is in a lowered position, thus allowingsteam from the upper portion of boiler 21 to vent freely to atmosphere.When the sleeve 41 is raised to a position wherein aperture 42 registerswith apertures 43 and 44, the vent aperture defined by the openings 46and 47 is substantially sealed.

Sleeve 41 is vertically moved by the action of a float ball 48rigidly-secured to the end of a float rod 49, the float rod having anintermediate bearing ball 50 which is rotatably-supported in a socketassembly 51 mounted in the wall of tank 16, as shown in FIGURE 6. Theend of rod 49 is provided with a lug 52 secured to sleeve 41 andslidably-engaged in an arcuate slot 53 provided therefor in thecylindrical wall 37. An inwardly-projecting headed button 54slidably-engages in an arcuate track 55 provided on the interior surfaceof shell 40, the button 54 being connected to the lug 52 and having ashank which extends through an aperture provided therefor in the sleeve41, so that the sleeve follows the movements of the button 54 and isguided through said movements by the provision of the registeringarcuate slot 53 and arcuate trackway 55. The arcuate slot 53 and arcuatetrackway 55 are concentric with the ball 50. Thus, movement of the floatball 48 in response to changes in the level of the water in chamber 19causes inverse corresponding movements of the valve sleeve 41. When thewater level drops below a predetermined safe amount, aperture 42 ismoved into registry with apertures 43 and 44, allowing steam from boiler21 to enter the upper portion of chamber 19, to cause replenishment ofthe Water by pumping action, as will be presently described. When thewater level in chamber 19 rises to a predetermined top-limiting value,aperture 45 registers with apertures 46 and 47, allowing free venting ofthe steam from chamber 21 to atmosphere while, at the same time, closingoff the apertures 43 and 44. This latter condition is illustrated inFIGURE 7. The provision of the safety valve 39 prevents excessivebuild-up of steam pressure by allowing the steam to release when apredetermined upper safe-limiting pressure is reached.

Tank 16 is provided with an emergency water-heating means which may beemployed in the event of a power failure such as the failure of a powersupply employed for the electric heating device 24. Thus, the bottomwall 23 of chamber 19 is formed with a depending well 56 which may beheated by any suitable heating means, such as a portable gas burner, orthe like, which may be positioned or mounted in any suitable mannerbeneath the well 56. The auxiliary burner is designated at 57 in FIG-URE 1, and this burner is of any conventional type arranged to beenergized by connecting thereto a suitable portable source of fuel, notshown.

The horizontal partition Wall 17 is formed with a valve opening 58, andpivoted in this opening is a generally circular valve disc 59, the dischaving the transverse pivotal axle 60 whose ends are supported inopposite marginal portions of opening 58, as shown in FIG- URE 4. Theopening 58 has the inwardly-projecting marginal lip 61 at one side ofits upper portion and an inwardly-projecting marginal lip 62 at theother side of its lower portion, and the disc is correspondinglyrecessed to sealingly-receive the marginal lips 61 and 62. Thus, thelips 61 and 62 act as limiting means to prevent rotation of the disc 59past its horizontal sealing position shown in FIGURE 2. Disc 59 may berotated to an open position, such as that shown in dotted view in FIGURE2, and in full-line view in FIGURE 1. Disc 59 is actuated by a rod 63pivotally-connected to the disc at 64, the disc being formed with aradial slot 65 which receives the flattened lower end portion 66 of rod63, as shown in FIGURES 2, 4 and 5. The wall of slot 65 is formed withthe respective detent recesses 67 and 68 spaced angularly relative totransverse pivot pin 64 by approximately 90, and being adapted to belockinglyand-releasably-engaged by a ball detent 69 disposed in a recess70 provided in the end of flatted rod portion 66 and biased outwardly bya spring 71, as shown in FIG- URE 5. Thus, the ball detent 69 engageseither in the recess 67 or in recess 68, to lock the disc 59 either inth horizontal closed position thereof of FIGURES 2 and 3, or in the openposition thereof shown in FIGURE 1, or in dotted view in FIGURE 2. Theball 69 is yieldable responsive to a relatively moderate force appliedto the rod 63, in a manner presently to be described.

Rod 63 may be made of any suitable material, such as solid rigid plasticrod material. The top end of rod 63 is tightly-secured in a dependingsleeve 72, which may be made from copper tubing, or the like. The topleft corner of sleeve 72, as viewed in FIGURE 2, is hinged at 73 to theunderside of a valve block 74 mounted on the top wall 20 of upperchamber 18 over a vent opening 75 provided in said top wall. The valveblock 74 comprises a body of suitable relatively-flexible material, suchas hard rubber, or the like, formed with a stationary stop portion 76,which may be of generally triangular longitudinal cross-section, asshown in FIGURE 2, and which is formed with a groove or recess 77 whichtightly-receives a marginal portion of the opening 75 in top wall 20,thus securing the block 74 in its operating position shown in FIGURES 1and 2. The block 74 has the movable flap valve portion 78 which isrotatable relative to the stationary stop portion 76 around the axis ofa transverse hinge element 79 provided between the lower end portions ofthe rear face 80 of flap 78 and the inclined front face '81 of stopelement 76.

The underside of the flap member 78 is formed with a depending hollowannular rib 82 surrounding the hinged top end portion of sleeve 72, theinterior of rib 82 being filled with air. The flap block 78 is providedwith a sealed metal capsule 84 located above the hollow rib 82, thecapsule being of copper, or other suitable metal, and a quantity ofmercury 85 is contained therein. Rigidlysecured to the fla-p block 78immediately beneath capsule 84 and depending into the top end of sleeve72 is a downwardly-projecting inclined stop pin 86 which serves as ameans to guide the swinging movement of sleeve 72 relative to the valveflap block 78. As shown in FIGURE 3, the guide pin element 86 may havean arcuate cross-sectional shape to conform with the inside contour ofsleeve 72. The mass of mercury 85 serves a special function in that itsacts as a triggeringmeans to cause the flap block 78 to swing downwardlyfrom the open dotted-view position thereof shown in FIGURE 2 to theclosed full-line view position thereof responsive to the expansion ofthe mercury when exposed to steam. Actually, as will be presentlydescribed, the heat transfer takes place through the relatively thinhighly-conductive wall of the capsule 84, and the location of thecapsule is such that the expansion of the mercury causes a mechanicalimbalance of suflicient degree to overcome the forces acting to supportflap block 78 in its open position. Specifically, there forces comprisethe resistance of the detent recess 68 to the biasing force of the balldetent element 69 and the biasing spring 71 associated with the detentball 69, together with a practically negligible upward force exerted onthe block 78 by the steam flowing through opening 75 from chamber 18. Aswill be presently explained, the closing action of block 78 is assistedby the fact that condensation of steam takes place in chamber 18,producing a vacuum-therein, whereby atmospheric pressure cooperates withthe expanding action of the mercury mass 85 to'move the valve flap blocktoward its closed position.

The stop member 76 limits the upward movement of the flap element 78substantially to the dotted position thereof shown in FIGURE 2, and thefull-view position thereof shown in FIGURE 1. As will be presentlyexplained, in order to rotate the flap block element 78 upwardly fromthe full-line position thereof of FIGURE 2 to the dotted-view positionthereof, among other things, it is necessary 'to overcome theresistanceto movement provided by the actionof. detent bally69 on-recess 67. Aswill be presently explained, this is accomplished by the building up offluid pressure in the upper portion of chamber 18 resulting from thefilling up of said chamber with liquid 'fromthe source12 drawn into thechamberby suction;

In. operation, as the level of the water, shown at 90 in FIGURE 1, inthe lower chamber 19- drops, the ball 48 moves downwardly andeventuallyreaches a bottom- .limiting position wherein sleeve 41 iselevated so as to move opening 42 into registery with apertures 43 and44 (FIGURE 7). Steam from boiler 21 then is'allowed'to pass into theupper portion of chamberv 19, and thence through opening 58, normallyuncovered, into the upper chamber 18. The steam passes upwardly throughthe top opening 75 and flows past the underside of the flap block 78,heating the capsule. 84, and-eventually causing the mass of mercury 85therein to expand, whereupon the mercury mass shifts its center ofgravity rightwardly, as

'viewed in FIGURE 1, sufiiciently to cause it to exert a downward forcesuflicient to overcome the holding action of detent ball 69 relative torecess 68.

It will be seen from FIGURE 2 that in the open position of the lowervalve disc 59, the valve disc is slightly off dead-center position, sothat it can readily rotate in a clockwise direction from the dotted-viewposition thereof of FIGURE 2 toward the full-line position thereof,responsive to a relatively moderate downward force exerted on the rod63.

The downward rotation of valve flap block 78 from the dotted-viewposition thereof to the full-line position thereof in FIGURE 2simultaneously swings the bottom valve disc 59 to its closed position,so that both the upper valve element and the lower valve element of thetandemvalve system close simultaneously. Previously, the steam enteringthe upper chamber 18 has replaced all the air in said upper chamber,which escapes out through the opening 75, so that when the valve flapblock 78 closes, there is only a relatively small amount of air left inchamber 18. After closure of the flap block 78 and the bottom valve disc59, the steam in chamber 18 continues to condense (the condensation ofthe steam commencing even before the closure of valve flap element 78)so that a vacuum is formed in chamber 18 which causes water to be drawninto the chamber from the source 12 through the conduit 13. The vacuumis tightly held by the expansion of hollow annular rib 82 caused by thepull of the vacuum acting relative to the pressure of the air inside thehollow rib 82. As the vacuum in chamber 18 is reduced responsive to thefilling of the chamber with water, the suction pull on the hollow rib 82diminishes, becoming entirely released substantially as the water levelreaches and exerts buoyant force on said hollow rib. The water rises inchamber 18. until it comes into contact with the copper tubing 72, whichis in thermal contact with the capsule 84, whereby heat is conductedaway from the capsule to a suflicient extent to cool the mercury 85 andcontract it sufficiently so that flap block 78 is swung upwardly by thebuilding up of the fluid pressure in the top portion of chamber 18(compression of the small amount of retained air and vapor in the upperportion of the chamber). The upwardly-swinging movement of the flapblock element 78 is facilitated by the shift of the center of gravity ofthe contracted mercury 85 to the left, as viewed in FIGURE 2. The upwardforce exerted on flap block element 78 is sufficient to overcome theresistance of detent ball 69 with respect to recess 67 as well as thegravitational force of the elements of the tandem-valve assembly. There-opening of the bottom valve disc 59 allows the water admitted tochamber 18 to fiow downwardly through opening 58 into the bottom chamber19. Sufiicient water is in this way admitted so that the float ball 48rises sufliciently to close the steam-admission passages 43, 44 by thedescent of sleeve element 41 to its sealing position, such as that shownin FIGURE 7, and to simultaneously move the sleeve aperture 45 intoregistry with the openings 46, 47 to allow steam to vent freely to theatmosphere. The parts thus return to the normal positions thereof shownin FIGURE 1, and remain in these positions until pumping action is againrequired, for example, by the dropping of the level of the water in thelower chamber 19, as above-described.

As above-mentioned, condensation begins as soon as steam enters theupper chamber 18, whereby the pressure in the upper chamber 18 begins todrop and becomes less than atmospheric shortly after the steam has beenadmitted thereto through opening 58. Thus, shortly after the majorportion of the air in chamber 18 has been released through opening 75,atmospheric pressure hegins to act on the valve flap block 78. Thiscombines with the shifting of the center of gravity of the expanded massof mercury 85 to cause the flap element 78 to be lowered to closedposition. The vacuum developing in chamber 18 also acts on the undersideof the annular hollow rib 82, as well as on the remaining bottom surfaceportion of flap element 78 to urge the flap element downwardly. The factthat the annular rib 82 is hollow and air-filled makes it buoyant, sothat in the event the water level in chamber 18 rises so that it beginsto approach top wall 20, the buoyancy of the rib 82 insures the openingof valve block element 78 before chamber 18 becomes completely filled.

The flap valve element 74 is normally open, namely, is in thedotted-view position thereof shown in FIGURE 2, and remains open exceptwhen pumping action occurs responsive to the drop in level of the liquid90 in the lower chamber 19 to a bottom-limiting value such as to causethe valve sleeve aperture 42 to move into registry with the apertures 43and 44, as above-described.

The capsule 84 which extends substantially horizontally in the closedposition of the valve element 78 is thus in an inclined position in thenormal state of the flap valve element 78, as shown in FIGURE 2 indotted view. The hinge connection 73 is located approximately one-thirdthe distance between the lower and upper ends of the capsule, as seen indotted section in FIGURE 2. Thus, the distance between the hingeconnection 73 and the lower end of the capsule is approximatelyone-third the entire length of said capsule. The major portion of themercury 85, in its cold condition is, therefore, located between thehinge connection 73 and the lower end of the capsule. When the capsuleis exposed to the hot vapor escaping through the opening 75, asabove-described, the mercury 85 expands sufliciently so that aconsiderable quantity thereof extends outwardly past the pivotconnection 73 in the direction of the free end of the flap valve element78, and the weight of the expanded mercury is thus sufficient toovercome the relatively light holding resistance provided by thespring-biased detent ball 69 in cooperation with the detent recess 68.

As will be readily apparent, the liquid pumping mechanismabove-described has substantially universal application and can bereadily employed for pumping water or, with minor changes, for pumpinggas, oil, or other fluids.

While a specific embodiment of an improved fluid pump has been disclosedin the foregoing description, it will be understood that variousmodifications within the spirit of the invention may occur to thoseskilled in the art. Therefore, it is intended that no limitations beplaced on the invention except as defined by the scope of the appendedclaims.

What is claimed is:

1. A liquid pump comprising an upstanding tank having an upper chamberand a lower chamber with a partition wall between said chambers, aliquid-inlet conduit connected to said upper chamber, said inlet conduitleading to a supply source of liquid, a liquid-outlet conduit connectedto said lower chamber, means to generate hot vapor in the upper portionof the lower chamber, said upper chamber having a top wall,tandem-coupled valves in said top wall and said partition wall, saidtandem-coupled valves being normally open, means to close thetandem-coupled valves at times responsive to exposure thereof to hotvapor, whereby to trap condensing vapor in the upper chamber and producevacuum therein and to draw liquid from the source into the upper chamberthrough the inlet conduit, and means to re-open the tandem-coupledvalves responsive to the reception of a substantial quantity of liquidin said upper chamber.

2. A liquid pump comprising an upstanding tank having an upper chamberand a lower chamber with a partition wall between said chambers, aliquid-inlet conduit connected to said upper chamber, said inlet conduitleading to a supply source of liquid, a liquid-outlet conduit connectedto said lower chamber, a liquid boiler, means communicatively-connectingthe lower portion of the lower chamber to the boiler to furnish liquidthereto, vaporadmission valve means between said boiler and the upperportion of the lower chamber, means operating said vaporadmission valvemeans in accordance with the liquid level in said lower chamber, saidupper chamber having a top wall, tandem-coupled valves in saidlast-named top wall and said partition wall, said tandem-coupled valvesbeing normally open, said vapor-admission valve means being constructedto admit hot vapor from the boiler into the upper portion of the lowerchamber responsive to a predetermined low level of liquid in said lowerchamber, means to close the tandem-coupled valves responsive to exposurethereof to the hot vapor, whereby to trap condensing vapor in the upperchamber and produce vacuum therein and draw liquid from the supplysource into the upper chamber through the inlet conduit, and means tore-open the tandem-coupled valves responsive to the reception of asubstantial quantity of liquid in said upper chamber, whereby to refillthe lower chamber responsive to the re-opening of said tandem-coupledvalves.

3. The liquid pump of claim 2, and wherein the means operating thevapor-admission valve means comprises a float member in the lowerchamber, and means mechanically-coupling the float member to thevapor-admission valve means.

4. The liquid pump of claim 2, and wherein the vaporadmission valvemeans comprises a vertical conduit communicating with the top of saidboiler and secured to the side-wall of the lower chamber, with acommunication port between the vertical conduit and the upper portion ofthe lower chamber, an apertured valve sleeve slidablymounted in thevertical conduit, a float member in the lower chamber, and meansmechanically-coupling said float member to said apertured valve sleeve,said sleeve having an aperture registrable with said communication portresponsive to the descent of said float member to a predetermined heightin said lower chamber.

5. The liquid pump of claim 2, and wherein said tandem-coupled valvescomprise a first flap valve element pivoted over an aperture formed inthe top wall of the upper chamber, a second flap valve element pivotedin an aperture formed in the partition wall, and link meansinterconnecting said flap valve elements.

6. The liquid pump of claim 5, and wherein the tandemcoupled valves areprovided with yieldable detent means releasably-holding thetandem-coupled valves either in fully-opened or fully-closed positionsand wherein said means to close the tandem-coupled valves comprises asubstantially longitudinally-extending metal capsule in the first flapvalve element containing a quantity of fluid materialthermally-expansible longitudinally away from the link connection to thefirst flap valve element responsive to heat sufiiciently and in adirection to overcome the holding force of the detent means.

7. The liquid pump of claim 6, and wherein the metal capsule is providedwith a depending heat-conducting metal portion extending into the upperportion of the upper chamber and engageable by liquid to cause thecapsule to be cooled.

8. The liquid pump of claim 7, and wherein the first flap valve elementis provided with a depending hollow buoyant portion engageable by liquidin the upper portion of the upper chamber to exert upward opening forcethereon.

9. The liquid pump of claim 8, and wherein said dependingheat-conducting metal portion, forms the upper part of said link means.

10. The liquid pump of claim 9, and wherein said hollow buoyant portioncomprises an annular hollow airfilled rib depending from said first flapvalve element and surrounding said dependingheat-conducting metalportion.

11. The liquid pump of claim 10, and wherein said dependingheat-conducting metal portion comprises a metal tube hingedly-connectedat a top edge portion thereof to the underside of said first flap valveelement.

12. The liquid pump of claim 11, and a stop pin element depending fromsaid capsule into the metal tube and being engageable therewith to limitrelative movement of the first flap valve element with respect to saidmetal tube.

References Cited UNITED STATES PATENTS MacKenzie 103239 X R Sweeney103-239 X'R McCombs 103-239 Entrop 103240 Downs 103-235 10 10 3,091,2525/ 1963 Jones. 3,142,299 7/1964 Henderson. 3,261,905 7/ 1966 Allen.

DONLEY J. STOCKING, Primary Examiner WARREN J. KRAUSS, AssistantExaminer US. Cl. X.R.

